﻿// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.Collections.Generic;
using Microsoft.AspNetCore.Razor.Language.Intermediate;

namespace Microsoft.AspNetCore.Razor.Language.Components
{
    internal sealed class ComponentMarkupDiagnosticPass : ComponentIntermediateNodePassBase, IRazorOptimizationPass
    {
        public static readonly int DefaultOrder = 10000;

        public override int Order => DefaultOrder;

        protected override void ExecuteCore(RazorCodeDocument codeDocument, DocumentIntermediateNode documentNode)
        {
            var visitor = new Visitor();
            visitor.Visit(documentNode);
        }

        private class Visitor : IntermediateNodeWalker
        {
            private Dictionary<string, (string name, IntermediateNode node)> _attributes = new Dictionary<string, (string, IntermediateNode)>(StringComparer.OrdinalIgnoreCase);

            public override void VisitMarkupElement(MarkupElementIntermediateNode node)
            {
                for (var i = 0; i < node.Children.Count; i++)
                {
                    if (node.Children[i] is HtmlAttributeIntermediateNode attribute && attribute.AttributeName != null)
                    {
                        if (_attributes.TryGetValue(attribute.AttributeName, out var other))
                        {
                            // As a special case we want to point it out explicitly where a directive or other construct
                            // has emitted an attribute that causes a conflict. We're already looking at the lowered version
                            // of this construct, so it's easy to detect. We just need the original name to report the issue.
                            //
                            // Example: `bind-value` will set `value` and `onchange`.

                            var originalAttributeName =
                                attribute.Annotations[ComponentMetadata.Common.OriginalAttributeName] as string ??
                                other.node.Annotations[ComponentMetadata.Common.OriginalAttributeName] as string;
                            if (originalAttributeName != null)
                            {
                                other.node.Diagnostics.Add(ComponentDiagnosticFactory.Create_DuplicateMarkupAttributeDirective(
                                    other.name,
                                    originalAttributeName,
                                    other.node.Source ?? node.Source));
                            }
                            else
                            {
                                // This is a conflict in the code the user wrote. 
                                other.node.Diagnostics.Add(ComponentDiagnosticFactory.Create_DuplicateMarkupAttribute(
                                    other.name,
                                    other.node.Source ?? node.Source));
                            }
                        }

                        // Replace the attribute we were previously tracking. Then if you have three, the two on the left will have
                        // diagnostics.
                        _attributes[attribute.AttributeName] = (attribute.AttributeName, attribute);
                    }
                }

                _attributes.Clear();
                base.VisitMarkupElement(node);
            }

            public override void VisitComponent(ComponentIntermediateNode node)
            {
                for (var i = 0; i < node.Children.Count; i++)
                {
                    // Note that we don't handle ChildContent cases here. Those have their own pass for diagnostics.
                    if (node.Children[i] is ComponentAttributeIntermediateNode attribute && attribute.AttributeName != null)
                    {
                        if (_attributes.TryGetValue(attribute.AttributeName, out var other))
                        {
                            // As a special case we want to point it out explicitly where a directive or other construct
                            // has emitted an attribute that causes a conflict. We're already looking at the lowered version
                            // of this construct, so it's easy to detect. We just need the original name to report the issue.
                            //
                            // Example: `bind-Value` will set `Value` and `ValueChanged`.
                            var originalAttributeName =
                                attribute.Annotations[ComponentMetadata.Common.OriginalAttributeName] as string ??
                                other.node.Annotations[ComponentMetadata.Common.OriginalAttributeName] as string;
                            if (originalAttributeName != null)
                            {
                                other.node.Diagnostics.Add(ComponentDiagnosticFactory.Create_DuplicateComponentParameterDirective(
                                    other.name,
                                    originalAttributeName,
                                    other.node.Source ?? node.Source));
                            }
                            else
                            {
                                // This is a conflict in the code the user wrote. 
                                other.node.Diagnostics.Add(ComponentDiagnosticFactory.Create_DuplicateComponentParameter(
                                    other.name,
                                    other.node.Source ?? node.Source));
                            }
                        }

                        // Replace the attribute we were previously tracking. Then if you have three, the two on the left will have
                        // diagnostics.
                        _attributes[attribute.AttributeName] = (attribute.AttributeName, attribute);
                    }
                }

                _attributes.Clear();
                base.VisitComponent(node);
            }
        }
    }
}
